geographical region vs Deep South

geographical region and Deep South both are nouns.

Word	Noun	Adjective	Verb	Adverb
geographical region	Yes	No	No	No
Deep South	Yes	No	No	No

geographical region (noun)	Deep South (noun)
a demarcated area of the Earth	the southeastern region of the United States: South Carolina and Georgia and Alabama and Mississippi and Louisiana; prior to the American Civil War all these states produced cotton and permitted slavery